Self-lowering lifting jack



June 16, 1925. 1,541,868

w. .A. SPEAR SELF LOWE-RING LIFTING JACK Filed Jan. 12, 1924 2 Sheets-Sheet 1 IN VEN TOR. Mun-l? Fl. \SPEH/E 5 ATTORNEY June 16, 1925. 1,541,868

. W. A. SPEAR SELF LOWERING LIFTING JACK Filed Jan. 12, 1924 2 SheetsShee1. 2

ATTORNEY Patented June 16, 1925.

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snnriownriinemr mmer Application filed Janiiary 12, 1924. Serial K013853725;

a simple etiic'ifent Inechanisnifor controlling the lowering of the loadyand to provide such a mechanism which will be'j-comp'actin arrangen'lent', of a strong durable character and which can be produced ata relatively lowcost. r. Y. I

Other objects of, the invention will appear as the mechanism is described in detail.

In the accompanying drawings Fig.1 1 is a side elevation; partly broken, away; of a jack embodyingmy invention; Fig.2 is a front elevationof such a jack,;l partly broken away and partly insectioii; Fig.- 3 is a sectional view of the lowering mechanism; Fig. 4 is an end elevation .of the lowering mechanism with the end wall of the housing removed; and F 5 is a detail View 'ofthe locking pawl. v i

In these drawings Ihave illi'lstrated, one embodiment of my invention and have shown the saine as applied to a, lifting jack Off a well known type, butit will be understood that the lowering mechanism Ina ytake various forms and may be applied to jacks of various kinds without departing from the spirit of the invention. i

in the form here shown the jack comprises ahollow standard 1 having at its lower end a base portion 2 by means of which it supported normally in an upright llNlSllZlOTl. Mounted in the upper portiono't the standard and held against rotation relatively thereto is a nut 3 in which is mounted a screw threaded lifting element 4 hating at its upper end a. lifting head 5 adapted to engage the work or load to be lit'ted. Secured to the lifting head 5 and depending therefrom is a housing 6 the lower portifon or which iscylindrica'l and slidably mounted on the standard 1. Bigidly secured to the lifting element 4 is a beveled gear 7 with. which meshes a second leveled gear 8 which is rigidly secured to a shaft 9 journaled in suitable bearings car; 7 Med by the-housing 6. In the presentinstance, the shaft is journaled in bearings 1Q and 11 formed in a supplemental housinglQ which is rigidly enabling the supplemental housing to contain a lnbricant'for the mechanism whichis mounted therein shaft 9 projects beyond the supplemental housing .12 and'has rigidly secured thereto a ratchet wheel 13. leveijl l is rotatably mounted on the end of the shaft 9 and car ries a pawl 15 which cooperates with the ratchet wheel 13 to rotate the shaft 9 and thereby elevate the lifting element 4. I have here shown only the lever socketbut it will be understood that a spike or bar is removably li'lOIlIltetl inthis socket for actuating the lifting element.

. The lifting element 4 has a high pitch thread and is otherwise so arranged that, when unrestrained it .will move downwardly under the weight of the load. A shaft is so connected with thelitting element that it will be, rotated by the downward movement thereof and a retarding device or brake is provided for controlling thespeed 0t rot-a tion of the shaft. This device; preferably consistsof two parts; one of which is rotated by the shaft and one of which is held against. rotation and in order to impart to the first mentioned v speed which is sutficiently high to enable the proper controlto be had, l have interposed planetary gearing between the sa ine and the shaft. In the present instance, I have utilized the shaft 9, by ineans of which the lifting element is elevated, for controlling the loweringmovement of the lifting element. An annular gez'rr 16 mounted within the supplemental housing 12 concentric with the axis of the shaft Sand is rigidly secured to the inner wall oithe supplemental housing. A second gear '17 rotatablymounted on the shaft 9.21mi, in the present instance; is provided with an elongated hnb lS. This second gear arranged adjacent to the first mentioned gear and is provided withless teeth than the first mentioned gear. However, inthe present construction, the m0 gears are of approximately the same diaineteiy It will be noted that the second gear 1?,ben1g rotatably mounted on the shaft, may be held against rotation theresecured to the lnainllrou'sing (3 but has no communication therewith, thus The outer end at the pal-tot the retarding device a with during the lifting operation, and means are provided for connecting this gear with the shaft so that it will rotate therewith when the lifting element moves downwardly, that is, when the shaft 9 rotates in a reverse direction. As here shown, this means coinprises a clutch member 19 rigidly secured to the gear 17. A second clutch member 20 is slidably mounted on the shaft for movement into and out of cooperative engagement with the clutch member 19 and is held against rotation relatively to the shaft. The second clutch member 20 is yieldably pressed into engagement with the clutch member 19 and the two clutch members are provided with ratchet teeth so arranged that when the clutch member 20 rotates with the shaft dur ing the elevation of the lifting element its teeth will ride over the teeth of the other clutch member 19 and when the shaft rotates in a reverse direction the teeth of the clutch member 20 will operatively engage the teeth of the clutch member 19. Any suitable means may be provided for pressing the clutch member 20 toward the clutch member 19 but I preferably employ a series of springs, one of which is shown at 21, which act upon the clutch member 20 through balls 22 which serve to lessen the frictional contact between the parts. Rotatably mounted upon the hub 18 of the gear 17 is a supporting member 23 which carries a plurality of pinions 2st which extend across the peripheries of and mesh with the teeth of both gears, 16 and 17 In the present construction these pinions are rotatably mounted upon pins or studs 25 which are rigidly mounted in the supporting member 23, this member being here shown as a disk and being rotatable independently of the gear 17. It will be apparent, therefore, that when the shaft 9 is rotated in a reverse direction the clutch 20 will pick up the clutch 19 and cause the gear 17 to be rotated with the shaft. The rotation of the gear 17 also rotates the planetary pinions 2a and, inasmuch as the gear 16 is held against rotation, these planetary pinions are caused the gear 16 and they carry with them the supporting member 23. The ratio of the gear 16 to the gear 17 is such that the supporting member 23 will be rotated at a relatively high speed. A suitable device is provided to resist the rotation of the supporting member 23, thereby enabling the speed at which the load is lowered to be controlled. This device, which in effect constitutes a brake, may be of any suitable character and, as here shown, is in the form of a friction clutch comprising a clutch member 26 which is slidably mounted on the elongated hub 13 of the gear 17 and has a friction face adapted to engage a corresponding friction surface or face 27 on the supporting member or disk 23. The clutch member 26 is held to travel about against rotation with the hub 18 and, in the present instance, is provided in its opposite sides with recesses 28 into which extend pins 29 carried by a yoke 30. This yoke is pivotally mounted in the upper portion of the supplemental housing on an axis transverse to the shaft 9 and the pins 29 serve not only to hold the clutch member 26 against rotation but also to move the same toward or from the cooperating friction surface on the supporting member 23. Springs 31 act on the clutch member 26 to normally press the same toward the supporting member 23. Means are provided under the control of the operator for actuating the yoke to move the clutch into its inoperative position. As here shown, the yoke 30 has a downwardly extending arm 32 which is arranged to be engaged by a finger 33 rigidly secured to a short shaft 34': mounted in the wall of the supplemental housing and having secured to its outer end a short lever 35 by means of which it may be actuated. The arrangement of the finger 33 with. relation to the arm 32 on the yoke is such that when the lever 35 is moved in one direction the finger will engage the arm of the yoke and move the yoke outwardly so as to move the clutch member 26 into an inoperative position. The clutch member being spring pressed against the cooperating clutch member or supporting member 23 it will be obvious that the frictional contact between the two members may be varied by the manipulation of the lever 35 so as to allow the load to be lowered at the desired speed. lVhen the lever 35 is released the clutch members are. automatically moved into full engagement, in which positions they will have sufficient frictional contact to completely check the movement of the load. I have also provided means for positively locking the controlling mechanism against slipping after the load has been stopped in the desired position. To this end the supporting member 23 has formed on that face thereof adjacent to the yoke 30 a series of ratchet teeth 36 and the lever operated finger 33 is in the form of a pawl adapted to engage the ratchet teeth 36. A spring 37 is interposed between the finger or pawl and the arm 32 of the yoke so that the pawl will be moved into engagement with the ratchetteeth when the lever 35 is released. However, in order to prevent this pawl from engaging the ratchet teeth before the controlling device has completely checked the movement of the load I prefer to provide somemeans for retarding or delaying the action of the pawl. (if course. the spring 37 might be omitted and the pawl moved into engagement with the ratchet teeth by the manipulation of the lever after the movement of the load has been checked. It is desirable, however, that the pawl automatically engage the ratchet teeth thei'eforeprovided the saine with a retarding device in the form of a dash pot 38inWhieh is niounteda piston 39,the rod 40 of Whiohis connected by means of alinlt il with a finger 42 seouied to the fingeror pawl "lj'he dash pot is provided with an inlet port 43- controlled by a check valve 44 whiohperniits the entranoe of air to enable the quick inoi eineiit of the piston39 when the pawl isrnoted to its inoperative position. whei'ithpiston moves in the opposite direotionand the pawl moves toward the ratchet teethth'e clieekyalve 44' closes and the air eseapesthiotig'h a restricted port 45 which so retards the inoveinentof the pistonfan d eonseqiiently ofthe pawl 33, asto allow ample time for the brake or friction clutch to checlrthelnoyeinentbf the load before the pawl engages the ratchet teeth.

The operation of the device will be readily understood from the foregoing description and it will be apparent that I have provided controlling mechanism for a self-lowering jack which while very simple in its eoiistruction is highly eiiicient in its operation and will enable thedoWnWard mov'einent of the load to be absolutely controlled by the opera tor. The construction is of a Very strong diirahle Character but is siich that it can be produced at a relatively loW1eost-and further, of sueh a character that the parts are notliable to be disarranged or broken in operation. y

While I have shown and desoribed one embodinient of niylinventien I \irishitto be understood that I do'not desire to be limited to the details thereof as Various modifications may appear to a person skilled in the Having noi v fully described my invention, What I laiin as new and desire to 'seohre by Letters Patent is: v i I y I. In alifting jack, a standard, a lifting element su ported by saidstandard, a shaft connected with said liftin element for rotation thereby when said h ting element is moved downwardly, a device? to resist the rotation of saidshaft by said lifting element, aiidfplaiietary, gearing interposed between saiddeviee and said shaft. i

2. In a lifting jack; a standard, a lifting elenient supported said standard. a shaft connected with said lifting elen'ie'nt for rotation thereby when said lifting eleinent is moved downwardly, a deyioe to" resist the ronew of said shaft by said liftinlg eleinent; said device comprising two parts, plz'ine'tary gearing interposed bet-Ween one of said parts and saidshaft andlneaiis for moving the other part of said device into and out of so operatiye relation with the first mentioned part thereof, f e y H 3 In a lifting jack, a standard, a lifting eienientshpportedby said standard, a shaft connected with said lifting eleinent tori-etasen thereby when Said lifting element is moved doii 'niifardly, a deyi'ce to resist the rotation of said shaft by saidlifting element, planetary gearing operatively oiinected with said shaft, a friction nieiiibei coiineoted with said planetary gearin a seoond friction inefnber, ineaiis for yieldably pressing said friction member into oohtaet With the first mentioned friction member, and means for retfiacting said second friction ineihber.

e 4. In a lifting jack, :1 standard a liftingelement supported by said standard a shaft connected with said lifting, element for Totation thereby Wl'iGIl'Sfiltl lifting elen'ieiit is moved doti'iiwardly, a device to resist the rotation of said shaft by said liftingelement, planetary gearing interposed between said device and said shaft, and a ohitch to connect said planetary earing With said shaft.

5. In a lifting jack, a standarch a lifting element supported by said standard, a shaft coni'ieoted with said lifting elementfor rotation thereby when said lifting eleineiit lnoves downwardly, apair of gears niounted about said shaft, one of said gears being fixed Elf fin sh ietation and the other being: connected with said shaft for rotationt-herewith a supporting" member rotatable about the axis of said shaft, pinions Caiiried by said supporting nien'ibe'r and meshing with both of said gears, a friction device cooperating with said supporting member to resist the rotation of said shaft, and means for lnaiiip'- ulating said friotion device; I 6. manning jack a standard, lifting elem'elnt supported by said standard; a shaft ooiineeted with said lifting element for rotation thereby when said lifting" element moves downwardly, a. pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said shaft for rotation therewith; a supportin rhen'iher rotatable aboiit the axis of said shaft, pinions carried by said supporting memi ier and meshing with both of said gears said sup fior'ting lfi-lDbEi having a friction sin-face, a friction member mounted for movement into and out of contact iyitl'i the friction surface of said supporting ineniber and held against rotation; and means for aetnating said friction ineinber. y f

7. In a lifting jaoin a standard, a lifting}; elenient siipported by said standard, a shaft connected with said lifting element for r o tation thereby when said lifting element mores doitnii'ardly, a pair of gears mounted about said shaft, one of said gears beingfixed against rotation and the other being conn-eted with said shaft for rotation therewith, a. supporting nieinber rotatable about the of said shaft, pinionscari'ied by sai d supportingmember and meshing with Both of said gears, said supporting member ha:-

ing a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said sup porting member and held against rotation, an actuating member connected with said friction member, a lever, and means actuated by said lever to impart movement to said actuating member.

8. In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said liit'ting element moves downwardly, a pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said shaft for rotation therewith, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member and meshing with both of said gears, said supporting member having a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said supporting member and held against rotation, springs to move said friction member toward said supporting member, a pivoted actuating device ope 'ativcly connected with said friction member, a finger adapted to engage said actuating device to operat the same. and means for actuating said finger.

9. In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said lifting element moves downwardly, a pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said shaft for rotation therewith, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member and meshing with both of said gears, said supporting member having a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said supporting member and held against rotation, springs to move said friction member toward said supporting member, a pivoted actuating device operatively connected with said friction member, a finger adapted to engage said actuating device to operate the same, and means for actuating said linger, said supporting member having teeth and said finger being arranged to engage said teeth to lock said supporting member against rotation.

' 10. In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said lifting element moves downwardly, a pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said shaft for rotation therewith, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member and meshing with both of said gears, said supporting member having a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said supporting member and held against rotation, means for actuating said friction member, a device other than said friction member to lock said supporting member againstrotation, and means for first retracting said locking device and then imparting n'iovement to said actuating device to withdraw said friction member.

11. In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said lifting element moves downwardly, a pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said. shaft for rotation therewith, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member and meshing with both of said gears, said supporting member having'a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said supporting member and held against rotation, means for actuating said friction member, a locking member to engage said supporting member and hold the same against rotation, said locking member being so arranged that when moved into its inoperative position it will engage said actuating device and retract said friction member, and means for actuating said locking member.

12. In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for ro tation thereby when said lifting element moves downwardly, a pair of gears mounted about said shaft, one of said gears being fixed against rotation and the other being connected with said shaft for rotation therewith, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member and meshing with both of said gears, said supporting member having a friction surface, a friction member mounted for movement into and out of contact with the friction surface of said supporting member and held against rotation, means for actuating said friction member, a locking member to engage said supporting member and hold the same against rotation, said locking member being so arranged that when moved into its inoperative position it will engage said actuating device and retract said friction member, means for actuating said locking member, a spring interposed between said locking member and said actuating device,

mounted about said m tri s and means to retardtheaction of said locliias' device y i1 se ies, heatre abling said friction n, to sp rsely engage said supporting member before the latter is engaged by s a'id locking member, 13. Ina lifting ack, a standard, a'lifting element supported by saidstandard, means comprising a shaft foractuating said'lifting element, a pair'of gears mounted about said shaft, one of said gears being rigidly secured to a fixed support and the other of said gears being rotatable relatively to said shaft, a supporting member rotatable about the axis of said shaft, pinions carried by said supporting member, each meshing with both of said gears, means for connecting said rotatable gear with said shaft when said lifting element moves downwardly, and means to control the movement of said supporting, member. a

14. In a lifting jack, a standard, a lifting element supported by said standard, means comprising a shaft for actuating said lifting element, a pair of. gears mounted about said shaft, one of said gears being rigidly secured to a fixed support, a clutch to connect the other of said gears with said shaft when said lifting element is moved downwardly, a supporting member rotatable about the axis of said shaft, a plurality of pinions carried by said supporting member and each meshing with both of said gear and means acting on said supporting member to resist the movement thereof.

15. In a lifting jack, a standard, a lifting element supported by said standard, means comprising a shaft fo actuating said lifting element, a pair of gears mounted about said shaft, one of said gears being rigidly secured to a fixed support, a clutch to connect the other of said gears with said shaft when said lifting element is moved downwardly, a supporting member rotatable about the axis of said shaft, a plurality of pinions carried by said supporting menr ber and each meshing with both of said gears, said supporting member having a friction surface, a friction member slidably shaft and movable into and out of engagement with said friction surface and held against rotation, a pivoted yoke connected with said friction member, andmanually operated means for actuating said yoke.

16,111 a lifting jack, standard, a liftiug element supported bv said standard means comprising a shaft for actuating said lifting for said shaft, a pair of gears mounted about said shaft, one of said gears being rigidly secured to said housing, a clutch to connect the other of said gears with said shaft, a supporting member rotatable about the axis of said shaft, a plurality of pinions carried by said supporting member and each meshporting with said shaft element, a housing having bearings ing with both of saidgears, saidsupportmg member having a frict on surface,

friction member mounted about said shaft pi otally mo'unted'within saidyhousing and operatrvely "connected with said friction member, a shaftjournaledin said housing, a part carried by said last mentioned shaft and arranged to actuate said yoke, and a finger piece arranged exteriorly of said housing and secured to said last mentioned shaft.

17. In a lifting jack, a standard, a lifting element supported by said standard, means comprising a shaft for actuating said lifting element, a housing having bearings for said shaft, a pair of gears mounted about said shaft, one of said gears being rigidly secured to said housing, a clutch to connect the other of said gears with said shaft, a supporting member rotatable about the axis of said shaft, lurality of pinions carried by said supporting member and each meshing with both of said gears, said supmember having a friction surface, a

friction member mounted about said shaft for movement into and out of contact with the friction surface of said supporting member and held against rotation, a yoke pivotally mounted within said housing and operatively connected with said friction member, a shaft journaled in said housing, a part carried by said last mentioned shaft and arranged to actuate said yoke, said part being adapted to be moved into locking engagement with said supporting member when said friction member is in contact therewith, and a finger piece mounted on said last mentioned shaft exteriorly of said housing.

18; Ina lifting jack, a standard, alifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said lifting element is moved dowmvard, a retarding device for said shaft comprising a member connected for rotation thereby, when said shaft is rotated by the downward movement of said lifting element, a second member held against rotation and movable into and out of engagement with the first mentioned member, an actuating device for said second member, means to lock the first mentioned member against rotation, and means for moving said locking means into an inoperative position and causing the same to impart movement to said actuating device.

19 In a lifting jack, a standard, a lifting element supported by said standard, a shaft connected with said lifting element for rotation thereby when said lifting element is moved downward, a retarding device for said shaft comprising a member connected with said shaft for mtation-thereby when said shaft is rotated by the downward movement of said lifting element a second member held against rotation and movable into and out of engagement with the first mentioned member, an actuating device for said second member, means to lock the first mentioned member against rotation, and means to actuate 'said locking means, said locking means being so arranged that when moved into an inoperative position it will engage said actuating device and move said second member of said retarding device into an inoperative position.

In testimony whereof I a-Hix my signature hereto.

WALTER A. SPEAK. 

